The present invention relates to a body-weight support system. In particular, the present invention relates to an improved body-weight support system.
Successfully delivering intensive yet safe gait therapy to individuals with significant walking deficits presents the greatest challenges to even the most skilled therapists. In the acute stages of many neurological injuries such as stroke, spinal cord injury, or traumatic brain injury, individuals often exhibit highly unstable walking patterns and poor endurance, making it difficult to safely practice gait for both the patient and therapist. Because of this, there has been a big push in rehabilitation centers to move over-ground gait training to the treadmill where body-weight support systems can help minimize falls while at the same time raising the intensity of the training.
Numerous studies have investigated the effectiveness of body-weight supported treadmill training and have found that this mode of gait training promotes gains in walking ability similar to or greater than conventional gait training. Unfortunately, there is a gap in technologies available on the market for transitioning subjects from training on a treadmill to safe, weight-supported over-ground gait training. Since a primary goal of all individuals with walking impairments is to walk in their homes and in the community rather than on a treadmill, it is imperative that therapeutic interventions targeting walking involve over-ground gait training.
Some conventional support systems involve training individuals with gait impairments over smooth, flat surfaces. However, these systems have their limitations. In some systems, therapists are significantly obstructed from interacting with the subject, particularly their lower legs. For patients that require partial assistance to stabilize their knees and hips or help propel the legs, the systems present significant barriers between the patient and the therapist.
In other systems, the subject is required to physically drag the cart with them as they ambulate. Accordingly, rather than being able to focus on their own balance, posture, and walking ability, the subject is forced to compensate for the dynamics of the cart. For example, on a smooth flat surface, if the subject stops abruptly, the cart can continue to move forward and potentially destabilize the subject. This confounding effect may result in an abnormal compensatory gait strategy that could persist when the subject is removed from the device.
Another problem with some conventional systems is that they only provide static unloading to a subject. That is, under static unloading, the length of the shoulder straps is set to a fixed length, so the subject either bears all of their weight when the straps are slack or no weight when the straps are taught. Static unloading systems have been shown to result in abnormal ground reaction forces and altered muscle activation patterns in the lower extremities. In addition, static unloading systems limit the subject's vertical excursions that prevent certain forms of balance and postural therapy where a large range of motion is necessary.
Some conventional systems include a motorized over-ground gait trainer. While the trainer is motorized and programmed to follow the subject's movement, due to the mechanics of the actuators and overall system dynamics, there are significant delays in the response of the system so that the subject has the feeling that they are pulling a heavy, bulky cart in order to move, a behavior that may destabilize impaired patients during walking. Also, the device cannot traverse over-ground obstacles, such as ascending or descending stairs and rough terrain, making it limited to smooth surface gait training.
In another conventional support system, there is a limitation on the amount of body-weight support that is provided. In such a system, the body-weight support cannot be modulated continuously, but rather is adjusted before the training session begins and is then fixed at that level.
Moreover, in some support systems, the extent of the vertical travel of the system is limited. As a result, subjects cannot be raised from a wheelchair to a standing position, thereby restricting the use of the system to individuals with only minor to moderate gait impairments. Also, while the trolley of a support system may be fairly light, the subject must pull it along the over-head rail as they ambulate. As a result, the subject will feel the presence of a mass. Furthermore, the amount of unloading cannot be adjusted continuously since it requires the operator to manually increase the pressure in the actuator. Finally, the system does not monitor and store quantitative data of gait performance (e.g. subject's walking speed, distance walked, etc) so tracking improvements in gait is not possible.
Thus, there is a need for an improved body-weight support system that overcomes the limitations of the systems described above.